Country-Level RSV-Related Hospitalisation Rates Among Adults in High-Income Countries From an Ensemble Model Based on...

Understanding hospitalisation burden of respiratory syncytial virus (RSV)-associated acute respiratory infection (ARI) in adults is crucial for informing immunisation policy, yet such data are lacking in most high-income countries. We aimed to estimate country-level RSV-associated ARI hospitalisation rates among adults aged 18-64 and ≥ 65 years across high-income countries.

Data on adult RSV hospitalisation burden were identified from systematic literature review and national surveillance reports. A Bayesian adjustment was applied to account for underascertainment due to variability in diagnostic methods and clinical specimens. An ensemble modelling framework consisting of four independent approaches was developed to predict country-level RSV-associated ARI hospitalisation rates among adults aged 18-64 and ≥ 65 years across 63 high-income countries.

The ensemble model predicted a median annual RSV-associated ARI hospitalisation rate of 39 per 100,000 (interquartile range [IQR]: 33-48) for adults aged 18-64 years and 374 per 100,000 (318-468) for those aged ≥ 65 years across the 63 countries. The predicted rates varied substantially by continent; Africa (Seychelles) had the lowest RSV hospitalisation rate for both 18-64 and ≥ 65 years (17 and 188 per 100,000, respectively); the highest median RSV hospitalisation rate was in Oceania in adults aged 18-64 years (50 per 100,000; IQR: 31-51) and was in the Americas in adults aged ≥ 65 years (455 per 100,000; 428-518). Europe and Asia showed marked within-continent variations in RSV hospitalisation rates.

Although primary RSV disease burden data remain the gold standard for evidence-based vaccine policy development, this study offers a viable alternative reference for high-income countries lacking such data.